Organic light-emitting display apparatus and method of manufacturing the same

ABSTRACT

An organic light-emitting apparatus includes a substrate; a first electrode formed on the substrate, where the first electrode is a cathode, an electron injection layer formed to contact an upper surface of the first electrode and including Mg, an intermediate layer formed on the electron injection layer and including an organic emission layer, and a second electrode which is formed on the intermediate layer and is an anode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2011-0068964, filed on Jul. 12, 2011, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

1. Field

The present disclosure relates to an organic light-emitting apparatusfor improving image quality and a method of manufacturing the same.

2. Description of the Related Technology

Recently, display apparatuses have been replaced with thin-film typeflat panel display apparatuses that are portable. From among thin-filmtype flat panel display apparatuses, an organic light-emitting displayapparatus is a self-emitting display apparatus, has a larger viewingangle, better contrast characteristics, and a faster response rate, andthus has drawn attention as a next-generation display device.

An organic light-emitting display apparatus includes a first electrode,a second electrode, and an intermediate layer. The intermediate layerincludes an organic emission layer. When voltage is applied to the firstelectrode and the second electrode, the organic emission layer emitsvisible light.

However, an optical efficiency of the organic emission layer is limited,and thus improving image quality of the organic light-emitting displayapparatus is limited.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

Embodiments provide an organic light-emitting apparatus for improvingimage quality and a method of manufacturing the same.

According to one aspect, there is provided an organic light-emittingapparatus including: a substrate; a first electrode which is formed onthe substrate and is a cathode; an electron injection layer formed tocontact an upper surface of the first electrode and including Mg; anintermediate layer formed on the electron injection layer and includingan organic emission layer; and a second electrode which is formed on theintermediate layer and is an anode.

A contact angle between the electron injection layer and the firstelectrode can be in the range of 10° to 70°.

The first electrode can include indium tin oxide (ITO).

The organic light-emitting apparatus can further include a pixeldefining layer disposed on the first electrode and including an opening,wherein the electron injection layer and the first electrode each othercontact in the opening.

The electron injection layer can be disposed in the opening so as not todeviate from the opening.

The pixel defining layer can include a polymer material.

According to another aspect, there is provided a method of manufacturingan organic light-emitting apparatus, the method including: forming afirst electrode, which is a cathode, on a substrate; forming an electroninjection layer including Mg so as to contact an upper surface of thefirst electrode; forming an intermediate layer including an organicemission layer on the electron injection layer; and forming a secondelectrode, which is an anode, on the intermediate layer.

The forming of the electron injection layer can be performed in such away that a contact angle between the electron injection layer and thefirst electrode is in the range of 10° to 70°.

Plasma treatment can be performed between the forming of the firstelectrode and the forming of the electron injection layer.

The plasma treatment can be performed using nitrogen or oxygen.

The plasma treatment can be performed under a pressure of 30 mmTorr to100 mmTorr and a power atmosphere of 200 W to 1000 W.

The plasma treatment can be performed for 30 to 300 seconds.

The method can further include forming a pixel defining layer betweenthe forming of the first electrode and the forming of the electroninjection layer, wherein the pixel defining layer is formed on the firstelectrode and comprises an opening corresponding to the first electrode,wherein the plasma treatment is performed between the forming of thepixel defining layer and the forming of the electron injection layer,and the electron injection layer is formed in the opening so as not todeviate from the opening.

Ultra violet (UV) treatment can be performed between the forming of thefirst electrode and the forming of the electron injection layer.

The UV treatment can be performed under a normal pressure.

The UV treatment can include ozone.

The UV treatment can be performed for 10 to 60 seconds.

The method can further include forming a pixel defining layer betweenthe forming of the first electrode and the forming of the electroninjection layer, wherein the pixel defining layer is formed on the firstelectrode and comprises an opening corresponding to the first electrode,wherein the UV treatment is performed between the forming of the pixeldefining layer and the forming of the electron injection layer, and theelectron injection layer is formed in the opening so as not to deviatefrom the opening.

The forming of the first electrode can be performed using ITO.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail certain embodimentsthereof with reference to the attached drawings in which:

FIG. 1 is a schematic cross-sectional view illustrating an embodiment ofan organic light-emitting apparatus;

FIG. 2 is an enlarged view of region X illustrated in FIG. 1;

FIG. 3 is a schematic view of a contact angle between a first electrodeand an electron injection layer illustrated in FIG. 1;

FIG. 4 is a schematic cross-sectional view illustrating anotherembodiment of an organic light-emitting apparatus; and

FIGS. 5A through 5E are cross-sectional views sequentially illustratingan embodiment of a method of manufacturing an organic light-emittingapparatus.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Certain embodiments will be described in detail with reference to theaccompanying drawings.

FIG. 1 is a schematic cross-sectional view illustrating an embodiment ofan organic light-emitting apparatus 100.

Referring to FIG. 1, the organic light-emitting apparatus 100 includes asubstrate 101, a first electrode 110, an electron injection layer 120,an intermediate layer 130, and a second electrode 140.

The substrate 101 can be formed of a SiO₂-based transparent glassmaterial, but is not limited thereto and can be formed of anytransparent plastic material. The transparent plastic material can be aninsulating organic material, for example, at least one material selectedfrom the group consisting of polyethersulphone (PES), polyacrylate(PAR), polyetherimide (PEI), polyethyelenen napthalate (PEN),polyethyeleneterepthalate (PET), polycontact angle αene sulfide (PPS),polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC),and cellulose acetate propionate (CAP).

The substrate 101 can be formed of a metal, or it can be in the form offoil.

The first electrode 110 is disposed on the substrate 101. The firstelectrode 110 can be formed with a predetermined pattern by using aphotolithography method. A buffer layer (not shown) may be formedbetween the substrate 101 and the first electrode 110 so as to provide aflat surface on the substrate 101 and to prevent impurities frompenetrating the substrate 101. The buffer layer can be formed of SiO₂and/or SiNx.

The pattern of the first electrode 110 can be formed of a plurality ofstripe lines that are spaced apart from one another at a predeterminedinterval. Some embodiments of the organic light-emitting apparatus 100can be a passive matrix (PM)-type organic light-emitting apparatus. Anactive matrix type (AM) organic light-emitting apparatus is describedbelow.

The first electrode 110 functions as a cathode, and includes indium tinoxide (ITO).

A pixel defining layer 115 is disposed on the first electrode 110. Thepixel defining layer 115 includes an opening 115 a corresponding to thefirst electrode 110. The pixel defining layer 115 covers edges of thefirst electrode 110, and the opening 115 a overlaps with a predeterminedregion of an upper surface of the first electrode 110. The pixeldefining layer 115 can be formed of any of various insulating materialsand can include a high molecular material. The pixel defining layer 115can include a polyimide-based high molecular material.

The electron injection layer 120 is disposed on the first electrode 110to contact the upper surface of the first electrode 110. The electroninjection layer 120 is disposed in the opening 115 a so as not todeviate from the opening 115 a of the pixel defining layer 115 andcontacts the upper surface of the first electrode 110. The electroninjection layer 120 includes magnesium (Mg) so as to improve an electroninjection characteristic into the intermediate layer 130.

The electron injection layer 120 is disposed to have a contact angle αbetween about 10° and about 70° when contacting the first electrode 110.

When the contact angle α between the electron injection layer 120 andthe first electrode 110 is less than about 10°, the electron injectionlayer 120 may be formed not only in the opening 115 a of the pixeldefining layer 115, but also in the entire area of the pixel defininglayer 115. One opening 115 a of the plurality of openings 115 aillustrated in FIG. 1 may correspond to one sub-pixel. When the contactangle α between the electron injection layer 120 and the first electrode110 is less than about 10°, the electron injection layer 120 may beformed to extend across all the openings 115 a.

In such a case, there may be a problem in that all sub-pixels (notshown) are short-circuited due to the electron injection layer 120.Accordingly, it is preferable that the contact angle α between theelectron injection layer 120 and the first electrode 110 is equal to orgreater than about 10°.

When the contact angle α between the electron injection layer 120 andthe first electrode 110 is greater than about 70°, a contactcharacteristic of a contact surface between the electron injection layer120 and the first electrode 110, and a contact characteristic of acontact surface between the intermediate layer 130 and the electroninjection layer 120 are decreased. Thus, an electric field is notproperly applied to the intermediate layer 130, and in particular, tothe organic emission layer of the intermediate layer 130, andconsequently, an electrical characteristic and image quality of theorganic light-emitting apparatus 100 are decreased. Accordingly, thecontact angle α between the electron injection layer 120 and the firstelectrode 110 is equal to or less than about 70°.

The intermediate layer 130 is disposed on the electron injection layer120. The intermediate layer 130 includes at least an organic emissionlayer 132. The intermediate layer 130 also includes an electrontransport layer 131, a hole transport layer 133, and a hole injectionlayer 134.

The organic emission layer 132 can emit visible light having variouscolors, such as for example, red, green, and blue.

When the organic emission layer 132 emits red visible light, the organicemission layer 132 can include tetraphenyl naphthacene (Rubrene),tris(1-phenylisoquinoline)iridium(III) (Ir(piq)₃),bis(2-benzo[b]thiophene-2-yl-pyridine)(acetylacetonate)iridium(III)(Ir(btp)₂(acac)), tris(dibenzoylmethane)phenathroline europium(III)(Eu(dbm)₃(phen)),tris[4,4′-di-tert-buthyl-(2,2′)-bipyridine]ruthenium(III) complex(Ru(dtb-bpy)₃*2(PF₆)), DCM1, DCM2, Eu(thenoyltrifluoroacetone)3(Eu(TTA)3), butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran(DCJTB), and the like, and can also include a polymer emission materialsuch as a polyfluorene-based polymer or a polyvinyl-based polymer.

When the organic emission layer 132 emits green visible light, theorganic emission layer 132 can include3-(2-benzothiazolyl)-7-(diethylamino)coumarin (Coumarin 6)2,3,6,7-tetrahydro-1,1,7,7,-tetramethyl-1H,5H,11H-10-(2-benzothiazolyl)quinolidino-[9,9a,1gh]coumarin(C545 T), N,N′-dimethyl-quinacridone (DMQA),tris(2-phenylpyridine)iridium(III) (Ir(ppy)₃), and the like, that aregreen luminescent materials, and can also include a polymer emissionmaterial such as a polyfluorene-based polymer or a polyvinyl-basedpolymer.

When the organic emission layer 132 emits blue visible light, organicemission layer 132 can include oxadiazole dimer dyes (Bis-DAPOXP), spirocompounds (Spiro-DPVBi, Spiro-6P), triarylamine compounds,bis(styryl)amine (DPVBi, DSA),4,4′-bis(9-ethyl-3-carbazovinylene)-1,1′-biphenyl (BCzVBi), perylene,2,5,8,11-tetra-tert-buthylperylene (TPBe),9H-carbazole-3,3′-(1,4-phenylene-di-2,1-ethene-diyl)bis[9-ethyl-(9C)](BCzVB), 4,4-bis[4-(di-p-tolylamino)styryl]biphenyl (DPAVBi),4-(di-p-tolylamino)-4′-[(di-p-tolylamino)styryl]stilbene (DPAVB),4,4′-bis[4-(diphenylamino)styryl]biphenyl (BDAVBi),bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium III(FIrPic), and the like, that are blue luminescent materials, and canalso include a polymer emission material such as a polyfluorene-basedpolymer or a polyvinyl-based polymer.

Other embodiments of the organic emission layer 132 can be formed of anyof various materials.

The electron transport layer 131 is disposed on the electron injectionlayer 120, the organic emission layer 132 is disposed on the electrontransport layer 131, the hole transport layer 133 is disposed on theorganic emission layer 132, and the hole injection layer 134 is disposedon the hole transport layer 133.

In other embodiments, the intermediate layer 130 may include one or twoof the electron transport layer 131, the hole transport layer 133, andthe hole injection layer 134 instead of including all of them. In yetother embodiments, the intermediate layer 130 may include only theorganic emission layer 132.

The second electrode 140 is disposed on the intermediate layer 130. Thesecond electrode 140 functions as an anode. When the organiclight-emitting apparatus 100 is a PM-type organic light-emittingapparatus, the second electrode 140 can be in the form of stripecrossing the pattern of the first electrode 110 at right angles.

The second electrode 140 can be a reflective electrode or a transmissiveelectrode. When the second electrode 140 is a reflective electrode, thesecond electrode 140 is formed by forming a reflective layer includingsilver (Ag), Mg, aluminum (Al), platinum (Pt), palladium (Pd), gold(Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium(Li), calcium (Ca), or a combination thereof and disposing ITO, indiumzinc oxide (IZO), zinc oxide (ZnO), or In₂O₃ having a high work functionthereon.

When the second electrode 140 is a transmissive electrode, the secondelectrode 140 is formed of ITO, IZO, ZnO, or In₂O₃ having a high workfunction.

A sealing member (not shown) may be disposed on the second electrode 140so as to be opposite to a surface of the substrate 101. The sealingmember (not shown) can be formed to protect the intermediate layer 130against external moisture or oxygen and can be formed of glass orplastic, or alternatively, of a plurality of stacked structures eachincluding an organic material and an inorganic material.

In some embodiments, the organic light-emitting apparatus 100 includesthe electron injection layer 120 including Mg and thus can easilyimplement an inverted type having an improved electron injectioncharacteristic. In particular, when the first electrode 110 is a cathodeincluding ITO having a relatively high work function, an electroninjection characteristic can be decreased. However, since the electroninjection layer 120 including Mg is formed to contact the firstelectrode 110, an electron injection characteristic into theintermediate layer 130 through the first electrode 110 is not decreased.

Also, the contact angle α between the electron injection layer 120 andthe first electrode 110 can be in the range of about 10° to about 70°,so that a short circuit of sub-pixels due to the electron injectionlayer 120 may be prevented and image quality of the organiclight-emitting apparatus 100 may be improved by increasing a contactcharacteristic of a contact surface between the electron injection layer120 and the first electrode 110 and a contact characteristic of acontact surface between the intermediate layer 130 and the electroninjection layer 120.

FIG. 4 is a schematic cross-sectional view illustrating anotherembodiment of an organic light-emitting apparatus.

Referring to FIG. 4, an organic light-emitting apparatus 200 includes asubstrate 201, a thin film transistor (TFT), a first electrode 210, anelectron injection layer 220, an intermediate layer 230, and a secondelectrode 240. The TFT includes an active layer 203, a gate electrode205, a source electrode 207, and a drain electrode 208.

Hereinafter, components of each member will be described in detail.

A buffer layer 202 is formed on the substrate 201. The buffer layer 202can include SiO₂ or SiN_(x). The buffer layer 202 can also have astructure in which a plurality of layers are stacked. The buffer layer202 provides a flat surface on the substrate 201 and prevents moistureor foreign substances from penetrating the substrate 201.

The active layer 203 having a predetermined pattern is formed on thebuffer layer 202. The buffer layer 202 can be formed of an organic orinorganic semiconductor such as an amorphous or polycrystalline siliconmaterial, and includes source, drain, and channel regions. The gateinsulating layer 204 is formed on the active layer 203. The gateinsulating layer 204 can include any of various insulating materials.

The gate electrode 205 is formed on a predetermined area of the gateinsulating layer 204. The gate electrode 205 is connected to a gate line(not shown) through which an ON/OFF signal is applied to the TFT. Thegate electrode 205 can be formed of a metal such as Au, Ag, Cu, Ni, Pt,Pd, Al, or Mo or an alloy such as Al:Nd or Mo:W, but the presentinvention is not limited thereto.

An insulating interlayer 206 is formed on the gate electrode 205 so asto expose the source and drain regions of the active layer 203. Thesource electrode 207 and the drain electrode 208 can be formed torespectively contact the exposed source and drain regions of the activelayer 203.

A passivation layer 209 is formed to cover the TFT.

The first electrode 210 is formed on the passivation layer 209. Thepassivation layer 209 is formed to expose the drain electrode 208, andthe first electrode 210 is connected to the exposed drain electrode 208.

The first electrode 210 is a cathode and can include ITO.

A pixel defining layer 215 is formed on the first electrode 210. Thepixel defining layer 215 includes any of various insulating materialsand also includes an opening 215 a. The opening 215 a is formed tocorrespond to the first electrode 210. That is, the opening 215 a isformed to overlap with a predetermined area of an upper surface of thefirst electrode 210.

The electron injection layer 220 is disposed on the first electrode 210.The electron injection layer 220 is disposed in the opening 215 a so asnot to deviate from the opening 215 a of the pixel defining layer 215and contacts the upper surface of the first electrode 210. The electroninjection layer 220 includes Mg so as to improve an electron injectioncharacteristic into the intermediate layer 230.

Also, the electron injection layer 220 is disposed to have a contactangle between about 10° and about 70° when contacting the firstelectrode 210.

The intermediate layer 230 is disposed on the electron injection layer220. The intermediate layer 230 includes at least an organic emissionlayer (not shown). Also, similar to the above-described embodiment, theintermediate layer 230 can include at least one of an electron transportlayer, a hole transport layer, and a hole injection layer, or caninclude none of these layers.

The second electrode 240 is disposed on the intermediate layer 230. Thesecond electrode 240 functions as an anode. The second electrode 240 canbe commonly formed across all the sub-pixels (not shown) without havingan additional pattern.

When a voltage is applied through the first electrode 210 and the secondelectrode 240, visible light is emitted from the organic emission layerof the intermediate layer 230.

A sealing member (not shown) can be disposed on the second electrode240. The sealing member (not shown) can be formed to protect theintermediate layer 230 and other layers against external moisture oroxygen and can be formed of glass or plastic, or alternatively, can beformed of a plurality of stacked structures each including an organicmaterial and an inorganic material.

FIGS. 5A through 5E are cross-sectional views sequentially illustratingan embodiment of a method of manufacturing an organic light-emittingapparatus.

Referring to FIG. 5A, the first electrode 110 is formed on the substrate101. The first electrode 110 can be formed with a predetermined patternby using a photolithography method. A buffer layer (not shown) can beformed before forming the first electrode 110 on the substrate 101.

The first electrode 110 can be formed of a conductive material, such as,for example, ITO.

Referring to FIG. 5B, the pixel defining layer 115 is formed on thefirst electrode 110. The pixel defining layer 115 is formed to includethe opening 115 a formed with a predetermined pattern. The pixeldefining layer 115 can include a high molecular material, such as, forexample, polyimide.

The opening 115 a is formed to correspond to the first electrode 110.The pixel defining layer 115 is formed to cover edges of the firstelectrode 110, and the opening 115 a is formed to expose a predeterminedarea of the upper surface of the first electrode 110.

Referring to FIG. 5C, the exposed surface of the first electrode 110 anda surface of the pixel defining layer 115 are treated by using a surfacetreating material 500.

In some embodiments, the surface treating material 500 can be plasma. Asurface treatment process using plasma uses oxygen or nitrogen.

Such a plasma treatment process is performed under a pressure of about30 mmTorr to about 100 mmTorr, and a power atmosphere of about 200 W toabout 1000 W. The plasma treatment process may be performed for about 30to about 300 seconds.

The contact angle between the electron injection layer 120 and the firstelectrode 110, which are to be formed through the plasma surfacetreatment in a subsequent process, can be controlled as desired. Thecontact angle between the electron injection layer 120 and the firstelectrode 110 may be controlled to be within the range of about 10° toabout 70° through the plasma treatment.

In other embodiments, the surface treating material 500 may be ultraviolet (UV). A surface treatment process using UV can be performed byinjecting ozone together with UV, and ozone of more than about 10% canbe included. Such a UV surface treatment process is performed under anormal pressure. The UV used as the surface treating material 500 canhave a wavelength of about 185 nm or about 254 nm.

The UV surface treatment process can be performed for about 10 to about60 seconds.

The contact angle between the electron injection layer 120 and the firstelectrode 110, which are to be formed in a subsequent process, can becontrolled as desired through the UV surface treatment. The contactangle between the electron injection layer 120 and the first electrode110 can be controlled to be within the range of about 10° to about 70°through the UV surface treatment.

Referring to FIG. 5D, the electron injection layer 120 is formed. Theelectron injection layer 120 is formed to contact the upper surface ofthe first electrode 110. The electron injection layer 120 is disposed inthe opening 115 a so as not to deviate from the opening 115 a of thepixel defining layer 115 and contacts the upper surface of the firstelectrode 110.

An additional mask is not used to form the electron injection layer 120.When the electron injection layer 120 is formed to have a patterncorresponding to that of the opening 115 a, a photolithography processis not necessary.

As described above with reference to FIG. 5C, surface characteristics ofthe pixel defining layer 115 and the first electrode 110 change throughplasma treatment or UV treatment. Thus, a contact characteristic of acontact surface between the electron injection layer 120 including Mgand the pixel defining layer 115 including a high molecular material isdecreased. The electron injection layer 120 is formed only in theopening 115 a of the pixel defining layer 115 instead of being formed inthe entire area of the pixel defining layer 115.

A contact angle between the electron injection layer 120 including Mgand the first electrode 110 is in the range of about 10° to about 70°.

The electron injection layer 120 corresponds to the first electrode 110formed in the opening 115 a instead of corresponding to the entire pixeldefining layer 115 by allowing the contact angle between the electroninjection layer 120 and the first electrode 110 to be equal to orgreater than about 10°. Thus, the electron injection layer 120 can benaturally formed to have a desired pattern without performing aphotolithography process using an additional mask.

Also, since the contact angle between the electron injection layer 120and the first electrode 110 is equal to or less than about 70°, contactcharacteristics of contact surfaces between the electron injection layer120 and the first electrode 110 and between the intermediate layer 130and the electron injection layer 120 are improved.

Referring to FIG. 5E, the intermediate layer 130 and the secondelectrode 140 are formed on the electron injection layer 120, therebycompleting manufacture of the organic light-emitting apparatus 100.

The intermediate layer 130 includes at least the organic emission layer132. The intermediate layer 130 can also include at least one of theelectron transport layer 131, the hole transport layer 133, and the holeinjection layer 134 or can not include any layer.

The second electrode 140 is disposed on the intermediate layer 130. Thesecond electrode 140 functions as an anode. When the organiclight-emitting apparatus 100 is a PM-type organic light-emittingapparatus, the second electrode 140 can be in the form of stripecrossing the pattern of the first electrode 110 at right angles.

A sealing member (not shown) can be disposed on the second electrode 140so as to be opposite to a surface of the substrate 101.

According to embodiments of the method of manufacturing the organiclight-emitting apparatus 100, the organic light-emitting apparatus 100having an inverted structure and an improved image quality can be easilymanufactured. The electron injection layer 120 can include Mg when beingformed on the first electrode 110 so as to improve an electron injectioncharacteristic from the first electrode 110 into the intermediate layer130. In this regard, since the electron injection layer 120 includes ametal, the electron injection layer 120 should be independently formedin each sub-pixel instead of being formed across all the sub-pixels. Insome embodiments, the electron injection layer 120 can be patternedthrough plasma treatment or UV treatment without performing anadditional process before forming the electron injection layer 120. Theelectron injection layer 120 can be formed to have a desired patternwithout performing an additional process, for example, aphotolithography process.

The organic light-emitting apparatus and the method of manufacturing theorganic light-emitting apparatus can easily improve image quality.

While the present invention has been particularly shown and describedwith reference to certain embodiments thereof, it will be understood bythose of ordinary skill in the art that various changes in form anddetails can be made therein without departing from the spirit and scopeof the present invention as defined by the following claims.

What is claimed is:
 1. A method of manufacturing an organiclight-emitting apparatus, the method comprising: forming a firstelectrode, which is a cathode, on a substrate; forming an electroninjection layer comprising Mg so as to contact an upper surface of thefirst electrode such that a contact angle between the electron injectionlayer and the first electrode is in the range of about 10° to about 70°;forming an intermediate layer comprising an organic emission layer onthe electron injection layer; and forming a second electrode, which isan anode, on the intermediate layer.
 2. A method of manufacturing anorganic light-emitting apparatus, the method comprising: forming a firstelectrode, which is a cathode, on a substrate; forming an electroninjection layer comprising Mg so as to contact an upper surface of thefirst electrode; forming an intermediate layer comprising an organicemission layer on the electron injection layer; and forming a secondelectrode, which is an anode, on the intermediate layer, wherein plasmatreatment is performed between the forming of the first electrode andthe forming of the electron injection layer.
 3. The method of claim 2,wherein the plasma treatment is performed using nitrogen or oxygen. 4.The method of claim 2, wherein the plasma treatment is performed under apressure of about 30 mmTorr to about 100 mmTorr and a power atmosphereof about 200 W to about 1000 W.
 5. The method of claim 2, wherein theplasma treatment is performed for about 30 to about 300 seconds.
 6. Themethod of claim 2, further comprising forming a pixel defining layerbetween the forming of the first electrode and the forming of theelectron injection layer, wherein the pixel defining layer is formed onthe first electrode and comprises an opening corresponding to the firstelectrode, wherein the plasma treatment is performed between the formingof the pixel defining layer and the forming of the electron injectionlayer, and the electron injection layer is formed in the opening so asnot to deviate from the opening.
 7. A method of manufacturing an organiclight-emitting apparatus, the method comprising: forming a firstelectrode, which is a cathode, on a substrate; forming an electroninjection layer comprising Mg so as to contact an upper surface of thefirst electrode; forming an intermediate layer comprising an organicemission layer on the electron injection layer; and forming a secondelectrode, which is an anode, on the intermediate layer, wherein ultraviolet (UV) treatment is performed between the forming of the firstelectrode and the forming of the electron injection layer.
 8. The methodof claim 7, wherein the UV treatment is performed under a normalpressure.
 9. The method of claim 7, wherein the UV treatment comprisesozone.
 10. The method of claim 7, wherein the UV treatment is performedfor about 10 to about 60 seconds.
 11. The method of claim 7, furthercomprising forming a pixel defining layer between the forming of thefirst electrode and the forming of the electron injection layer, whereinthe pixel defining layer is formed on the first electrode and comprisesan opening corresponding to the first electrode, wherein the UVtreatment is performed between the forming of the pixel defining layerand the forming of the electron injection layer, and the electroninjection layer is formed in the opening so as not to deviate from theopening.
 12. The method of claim 1, wherein the forming of the firstelectrode is performed using ITO.